#include "dem.h"
#include "tinhtich45.h"
#include "tinhtong44.h"
#include "dem43.h"
void main()
{
int n;
cout<<"Nhap n= ";
cin>>n;
cout<<"Ket qua = "<<ham(n);
cout<<"tich la = "<<tinhtich(n);
cout<<"tong la = "<<tinhtong(n);
cout<<"Ket qua = "<<demso(n);
system("pause");
} 